1,014 research outputs found

    Two-axis flux gate magnetometer

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    Magnetometer uses single sensing head to measure magnetic flux density along two axes simultaneously. The sensor head consists of permalloy core and four windings. Two windings perform a multivibrator function, the two remaining windings sense magnetic fields. The smaller magnetometer performs same functions as more complex devices

    Jovimagnetic secular variation

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    Long term variations of a planetary magnetic field are one of the few observables available in the study of planetary interiors and dynamo theory. While variations of the geomagnetic field were accessible to direct measurement for centuries, knowledge of the secular variations of other planetary dynamos is limited. New limits on Jovimagnetic secular variations were found by comparison of a Jovian internal field model obtained from the Voyager 1 magnetic field observations at epoch 1979.2 with the epoch 1974.9 Pioneer 11 O4 model. No significant secular variation of either the magnitude or position of the Jovidipole is found for the years 1974.9 through 1979.2, although a small Earth-like variation cannot be ruled out

    The MAGSAT vector magnetometer: A precision fluxgate magnetometer for the measurement of the geomagnetic field

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    A description of the precision triaxial fluxgate magnetometer to be flown aboard the MAGSAT spacecraft is presented. The instrument covers the range of + or - 64,000 nT with a resolution of + or - 0.5 nT, an intrinsic accuracy of + or - 0.001% of full scale and an angular alignment stability of the order of 2 seconds of arc. It was developed at NASA's Goddard Space Flight Center and represents the state-of-the-art in precision vector magnetometers developed for spaceflight use

    Currents in Saturn's magnetosphere

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    A model of Saturn's magnetospheric magnetic field is obtained from the Voyager 1 and 2 observations. A representation consisting of the Z sub 3 zonal harmonic model of Saturn's planetary magnetic field together with an explicit model of Saturn's planetary magnetic field and a model of the equatorial ring current fits the observations well within r 20 R sub S, with the exception of data obtained during the Voyager 2 inbound pass

    Voyager 1 assessment of Jupiter's planetary magnetic field

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    An estimate of Jupiter's planetary magnetic field is obtained from the Voyager 1 observations of the Jovian magnetosphere. An explicit model for the magnetodisc current system is combined with a spherical harmonic model of the planetary field with both sets of parameters determined simultaneously using a nonlinear generalized inverse methodology. The resulting model fits the observations extremely well throughout the analysis interval (r 20 Jovian radii). The Jovian internal field model obtained from the Voyager 1 data is very similar to the octopole Pioneer 11 models. The best fitting magnetodisc lies in the centrifugal equator, 2/3 of the way between the rotational and magnetic equators, as appropriate for centrifugal loading of the magnetosphere by a cold plasma

    The Z3 model of Saturns magnetic field and the Pioneer 11 vector helium magnetometer observations

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    Magnetic field observations obtained by the Pioneer 11 vector helium magnetometer are compared with the Z(sub 3) model magnetic field. These Pioneer 11 observations, obtained at close-in radial distances, constitute an important and independent test of the Z(sub 3) zonal harmonic model, which was derived from Voyager 1 and Voyager 2 fluxgate magnetometer observations. Differences between the Pioneer 11 magnetometer and the Z(sub 3) model field are found to be small (approximately 1%) and quantitatively consistent with the expected instrumental accuracy. A detailed examination of these differences in spacecraft payload coordinates shows that they are uniquely associated with the instrument frame of reference and operation. A much improved fit to the Pioneer 11 observations is obtained by rotation of the instrument coordinate system about the spacecraft spin axis by 1.4 degree. With this adjustment, possibly associated with an instrumental phase lag or roll attitude error, the Pioneer 11 vector helium magnetometer observations are fully consistent with the Voyager Z(sub 3) model

    Phenomenological consequences of an interacting multicomponent dark sector

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    We consider a dark sector model containing stable fermions charged under an unbroken U(1) gauge interaction, with a massless dark photon as force carrier, and interacting with ordinary matter via scalar messengers. We study its early Universe evolution by solving a set of coupled Boltzmann equations that track the number density of the different species, as well as entropy and energy exchanges between the dark and visible sectors. Phenomenologically viable realizations include: (i) a heavy (order 1 TeV or more) leptonlike dark fermion playing the role of the dark matter candidate, with various production mechanisms active depending on the strength of the dark-visible sector portal; (ii) light (few GeV to few tens of GeV) quarklike dark fermions, stable but with suppressed relic densities; (iii) an extra radiation component in Universe due to dark photons, with temperature constrained by cosmic microwave background data, and in turn preventing dark fermions to be lighter than about 1 GeV. Extra constraints on our scenario stem from dark matter direct detection searches: the elastic scattering on nuclei is driven by dipole or charge radius interactions mediated by either Standard Model or dark photons, providing long-range effects which, however, are not always dominant, as usually assumed in this context. Projected sensitivities for next-generation detectors cover a significant portion of the viable parameter space and are competitive with respect to the model-dependent constraints derived from the magnetic dipole moments of leptons and cooling of stellar systems

    Implications of Pioneer-2 magnetic field models for Jupiter's decametric radio mission

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    The geometry and electron gyrofrequency were calculated for both the North and South feet of the Io-threaded flux tube at several altitudes as a function of sub-Io longitude for various multipole field models. The models predict a maximum surface gyrofrequency equal to the observed high frequency limit of the decameter-wave radio emission (DAM) and tend to favor a mechanism involving transverse propagation from a source in the Northern hemisphere. Calculations indicate that the beaming pattern of the emission may be determined by reflection from the ionosphere rather than by inherent beaming from the source region

    Contributions to the Fourth Solar Wind Conference

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    Recent results in interplanetary physics are examined. These include observations of shock waves and post-shock magnetic fields made by Voyager 1, 2; observations of the electron temperature as a function of distance between 1.36 AU and 2.25 AU; and observations of the structure of sector boundaries observed by Helios 1. A theory of electron energy transport in the collisionless solar wind is presented, and compared with observations. Alfven waves and Alvenic fluctuations in the solar wind are also discussed

    Józef Borodzicz, Na rusi gallicyjskiej Schyzma sie gotuje, Drukar Maryi Ziembińskiej, Chrzanowie, 1911.

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    Several research studies have argued that people evaluate incivilities of places as part of the process of estimating how safe they might be. The study presented here examined whether such an assumption is upheld when people are allowed to express their thoughts about places before rating how disordered a place seems to them. British students evaluated three residential areas with different levels of disorder. First, participants had to write their impressions about the places and then rate how disordered, risky and unsafe the places seemed to them. The qualitative analysis showed that despite participants referred to physical disorder, only few participants mentioned crime and safety. Results from the quantitative analysis revealed that as the more disordered a place was rated the more unsafe it was considered. Findings suggest both that disordered places not always elicit unsafe concerns and that the so predicted relationship between disorder and safety maybe method dependant
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